This invention relates to a tablet arm assembly for use in combination with a chair or seat, in which the tablet arm assembly is movable between a stored position and an operative position.
In fixed seating systems, it is common to mount a tablet arm to the side support of a seating assembly, such as in an auditorium or educational environment, so as to enable a seated person to take notes or the like. A tablet arm assembly typically includes a chair arm and a planar board or tablet defining an upper writing surface. This tablet is mounted to a movable mounting arrangement providing movement of the tablet relative to the chair arm between an operative position in which the tablet upper surface is substantially horizontal, and a stored position in which the tablet is moved either under the seat or downwardly and beside the side support of the seat.
It is an object of the present invention to provide a tablet mounting assembly for use with a seat or chair. It is another object of the invention to provide a tablet mounting assembly that is relatively simple in construction, and which provides ease of assembly and mounting to the chair arm. It is a further object of the invention to provide a tablet mounting assembly that provides convenient and quiet operation. It is yet another object of the invention to provide a tablet mounting assembly that can be easily repaired in the field.
In accordance with the invention, the tablet mounting assembly is interposed between the tablet and the chair arm. The mounting assembly generally includes a hinge mechanism having a bracket mounted to a bottom surface of the tablet, a connecting shaft mounted to another bracket on the hinge perpendicular to the pivot axis of the hinge, and inner and outer mounting collars secured to the chair arm. The inner and outer mounting collars are aligned to form a shaft retaining structure that is configured to support the connecting shaft for pivotal movement within the collars.
The connecting shaft has a key member that extends radially outward from the shaft. The shaft retaining structure formed by the mounting collar is configured to accommodate rotation of the key member along an arcuate key path between a front key stop and a rear key stop. Preferably, the arcuate key path allows approximately 180.degree. of rotation for the connecting shaft. Hinge rotation is preferably limited to 90.degree. through the use of lugs or some other means. This construction provides the user of the seat with convenient means of moving the tablet arm between an operative position wherein the upper surface of the tablet arm is substantially horizontal, to an intermediate position wherein the tablet arm is rotated about the hinge pivot axis to be substantially vertical, and finally into a storage position wherein the tablet arm is rotated about the shaft pivot axis downwardly and rearwardly to a position adjacent the chair arm next to the side of the seat.
The inner and outer mounting collars are preferably made from injection molded plastic such as nylon. The outer mounting collar has an axial opening extending through the body of the collar from an exposed side of the collar to an inner side of the collar. The outer mounting collar also includes a mounting flange on the exposed side that extends outward from the collar body. The outer mounting collar is preferably secured to the tablet support, such as the chair arm, by fastening the flange to the support with screws or bolts. The connecting shaft passes through the axial opening in the outer collar. An installation slot extends radially from and along the axial opening so that the shaft key member may be inserted through the outer collar for installation. The outer collar also preferably includes a key recess which accommodates rotation of at least a portion of the key member along the arcuate key path. The installation slot in the outer collar extends from the axial opening in a direction away from the arcuate key path. It is most preferable that the installation slot be located closer to the rear key stop than the front key stop because the rear key stop is normally subjected to lower forces than the front key stop when the tablet assembly is in use.
Similar to the outer mounting collar, the inner mounting collar preferably has a mounting flange also on its exposed side for mounting the collar to the tablet support. The inner collar has a recess on its inner side defining a core recessed portion that is aligned with the connecting shaft pivot axis and, also preferably a key recess portion. The core recessed portion pivotally supports the connecting shaft, and the key recess portion accommodates rotation of at least a portion of the key member along the arcuate key path as with the outer collar.
It is most preferable that the outer mounting collar include at least one alignment boss on the surface of its inner side, and that corresponding alignment indentations be located on the surface of the inner side of the inner mounting collar. When the inner and outer mounting collars are secured to the tablet support, the alignment boss resides within the alignment indentation. Further, both the inner and outer mounting collars have a flat portion on the outer circumferential surface of their respective bodies, and mounting plates on the tablet support contain openings having a corresponding geometry. These features aid in ensuring that the collar surfaces defining the shaft retaining structure are properly aligned during installation. Preferably, the inner and outer mounting collars are secured to the tablet support, such that the mounting collars are in axial compression. Under compression, the mounting collars are more effective at withstanding fatigue due to repetitive use. To further reduce problems due to fatigue, the mounting collars preferably contain stress reduction voids located within each respective collar body above the front and rear key stops.
The hinge mechanism of the present invention is generally comprised of a pivot bracket having at least one hinge barrel, a tablet support bracket having at least one hinge barrel, a hinge pin that pivotally connects the pivot bracket hinge barrel to the support bracket hinge barrel, and a connecting shaft with a key member. The tablet support bracket is attached to the bottom surface of the tablet, and the connecting shaft with the key member is attached to the hinge pivot bracket. It is preferred to provide a spring around the hinge pin which is supported by a sleeve, in order to provide a biasing force that cushions the motion of the tablet arm from the substantially vertical intermediate position to the substantially horizontal operative position. For servicing, the pivot bracket also includes access holes that facilitate access to fasteners securing the outer mounting collar to the tablet support.
Preferably, the tablet arm assembly of the present invention includes an arm rest cap covering the top surface of the tablet support which provides a flat and substantially horizontal surface for supporting the tablet support bracket on the bottom surface of the tablet when the tablet is in the substantially horizontal operative position. The arm rest cap is preferably comprised of a plastic material to facilitate quiet operation of the assembly. When the tablet arm is in the stored position, the plastic arm rest cap provides a comfortable arm rest for the user.
The invention also contemplates a particularly effective method of mounting a tablet arm to a seating assembly which uses an inner and outer mounting collar configured substantially in accordance with the foregoing summary. The method and its advantages are discussed in detail below in reference to the drawings. In another aspect of the present invention, an inner mounting collar and an outer mounting collar as explained above are provided as replacement parts for existing tablet arm assemblies.
Various other features, objects and advantages of the invention may be apparent to those skilled in the art upon reviewing the drawings and the following description thereof.